Sound-deadening undercoat material in rear wheelhouses

[NorCam]

Is there a technically correct material being used for sound-deadening undercoat material just as the factory sprayed in the rear wheelhouses? Most painters I know are using the typical rubberized undercoat which gives you a thin pebbly coating and is nothing like the thicker factory applied material?

1.) I'm wondering if anyone has a good source for the thicker stuff like the factory used and if they used a shutz gun and a pressure pot to apply it?

2.) Also wondering if that was the same material sprayed inside of the rear quarter panels and inside the doors & quarter window openings?

Thanks for any good info on materials used to replicate the stock products.